The coevolution of galaxy morphology and colour to z ~ 1
1 Institute of Physics, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406 Kielce, Poland
2 Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
3 Astronomical Observatory of the Jagiellonian University, Orla 171, 30-001 Cracow, Poland
4 National Centre for Nuclear Research, ul. Hoza 69, 00-681 Warszawa, Poland
5 INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Bologna, via Gobetti 101, 40129 Bologna, Italy
6 INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
7 INAF–Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate, Italy
8 INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, 20133 Milano, Italy
9 Dipartimento di Fisica, Università di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy
10 INAF–Osservatorio Astrofisico di Torino, 10025 Pino Torinese, Italy
11 Aix-Marseille Université, CNRS, CPT (Centre de Physique Théorique) UMR 7332, 13288 Marseille, France
12 Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
13 INFN, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
14 INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone (RM), Italy
15 INAF–Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste, Italy
16 National Centre for Nuclear Research, ul. Hoza 69, 00-681, Warszawa, Poland
17 Dipartimento di Fisica e Astronomia – Università di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
18 INFN, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
19 Institute d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, 75014 Paris, France
20 Division of Particle and Astrophysical Science, Nagoya University, Furo-cho, Chikusa-ku, 464-8602 Nagoya, Japan
21 Institute of Cosmology and Gravitation, Dennis SciamaBuilding, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3FX, UK
22 INAF–Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
23 IRAP, 9 av. du colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
24 Astronomical Observatory of the University of Geneva, ch. dÈcogia 16, 1290 Versoix, Switzerland
Received: 17 May 2016
Accepted: 12 October 2016
Context. The study of the separation of galaxy types into different classes that share the same characteristics, and of the evolution of the specific parameters used in the classification are fundamental for understanding galaxy evolution.
Aims. We explore the evolution of the statistical distribution of galaxy morphological properties and colours combining high-quality imaging data from the CFHT Legacy Survey with the large number of redshifts and extended photometry from the VIPERS survey.
Methods. Galaxy structural parameters were combined with absolute magnitudes, colours and redshifts in order to trace evolution in a multi-parameter space. Using a new method we analysed the combination of colours and structural parameters of early- and late-type galaxies in luminosity-redshift space.
Results. We find that both the rest-frame colour distributions in the (U−B) vs. (B−V) plane and the Sérsic index distributions are well fitted by a sum of two Gaussians, with a remarkable consistency of red-spheroidal and blue-disky galaxy populations, over the explored redshift (0.5 < z < 1) and luminosity (−1.5 < B−B∗ < 1.0) ranges. The combination of the rest-frame colour and Sérsic index as a function of redshift and luminosity allows us to present the structure of both galaxy types and their evolution. We find that early-type galaxies display only a slow change in their concentrations after z = 1. Their high concentrations were already established at z ~ 1 and depend much more strongly on their luminosity than redshift. In contrast, late-type galaxies clearly become more concentrated with cosmic time with only little evolution in colour, which remains dependent mainly on their luminosity.
Conclusions. The combination of rest-frame colours and Sérsic index as a function of redshift and luminosity leads to a precise statistical description of the structure of galaxies and their evolution. Additionally, the proposed method provides a robust way to split galaxies into early and late types.
Key words: cosmology: observations / galaxies: general / galaxies: structure / galaxies: evolution / galaxies: statistics
Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programs 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://vipers.inaf.it/
A table of the fitted parameters is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A120
© ESO, 2017